momentum 1.1.6

momentum: ^1.1.6 copied to clipboard

• Restart the app with new momentum instance.
• To easily implement, in you main.dart create a method that returns Momentum instance.

  void main() {
    runApp(momentum()); // call the method here instead of instantiating the Momentum.
  }
  
  Momentum momentum() {
    return Momentum(
      child: MyApp(),
      controllers: [
        LoginController(),
        SessionController()..config(lazy: false, enableLogging: true),
        TimerController()..config(maxTimeTravelSteps: 5),
        TimeclockController(),
        AppController()..config(lazy: false, enableLogging: true),
        SettingsController()..config(lazy: false),
      ],
      services: [
        Router([
          Login(),
          Home(),
          Settings(),
          LanguageSelection(),
          FontScale(),
        ]),
      ],
      enableLogging: false,
      onResetAll: (context, resetAll) async {
        await Momentum.of<SessionController>(context).clearSession();
        resetAll(context);
        Router.goto(context, Login);
      },
    );
  }
  

• You can then call Momentum.restart(...) down the tree:

  Momentum.restart(context, momentum()); // call momentum() which is a top level function.
  

New feature added: Services.

Inject anything into momentum and use them down the tree inside widgets or controllers.

Example code:

// main.dart
Momentum(
  controllers: [...],
  services: [
    ApiService(),
  ],
  child: MyApp(),
  ...
)

// *.controller.dart
void loadUser() async {
  model.update(loadingUser: true);
  var apiService = getService<ApiService>();
  var user = await apiService.getUser(); // load data from server. asynchronous
  model.update(loadingUser: false, user: user);
}

• You have to turn lazy loading off to enable this feature.
• Lets say one of your controllers implements bootstrap() method asynchronously and it loads a data that takes seconds to finish:

    @override
    void bootstrap() async {
      // assuming we are loading some complex and big data here.
      var appSettings = await apiService.getAppSettings();
      model.update(appSettings: appSettings);
    }
  

• Now, imagine apiService.getAppSettings() takes 3-5 seconds to load. Before your MyApp() gets actually loaded, momentum will await this boostrap method and show a loading widget until it finishes. Means, you can now do anything you want with bootstrap() method synchronous or asynchonous. It is safe to call model.update(...) in this method.

New feature: dontRebuildIf parameter for MomentumBuilder.

• This method will be called after model.update(...) right before the builder.

• isTimeTravel is also provided that indicates if the model was updated by time travel methods .backward() or .forward(), returning it directly means you don't want to rebuild if an update was done with time travel method.

• Two new properties was also added: MomentumController.prevModel and MomentumController.nextModel which are properties from model history and their meaning is quite obvious. The prevModel is the previous state and nextModel is the next state which will only have a value if you use .backward() method. If you are on latest snapshot of the model nextModel will be null.

• Take a look at this example, The widget is displaying a time format HH:mm and TimerController ticks every 500ms for accuracy. We only need to rebuild if minute property is changed, that's where dontRebuildIf parameter comes.

    MomentumBuilder(
      controllers: [TimerController],
      dontRebuildIf: (controller, isTimeTravel) {
        var timer = controller<TimerController>();
        var prevMinute = timer.prevModel.dateTime.minute;
        var currentMinute = timer.model.dateTime.minute;
        var minuteUnchanged = currentMinute == prevMinute;
        return minuteUnchanged; // don't rebuild the widget if "minute" is unchanged.
      },
      builder: (context, snapshot) {...},
    )
  

• WARNING: This method is the same as any other builder or build methods, do not call model.update(...) or anything that calls build method, for example setState(...). You'll get an infinite loop.

• updated onResetAll to support widget operation before actually reseting all models.
• improved README, added lots of new contents.